Question

sin 5A + 2 sin 8A + sin 11A
sin 8A/sin 8 A + 2 sin 11A +sin 14 A=sin8a/sin11a
​

Answer 1

Answer:

Step-by-step explanation:

Sin5A + 2Sin8A+ Sin11A/Sin8A + 2Sin11A + Sin14A

=> (Sin11A + Sin5A)+2Sin8A/(Sin14A+Sin8A)+2Sin11A

//We know that SinC + SinD = 2Sin(C+D/2)Sin(C-D/2)

=> 2Sin(5A+11A/2).Sin(11A-8A/2) + 2Sin8A / 2Sin(14A+8A/2)Sin(14A-8A/2) +

                                                                                                        2Sin11A  

=> 2Sin8A.Sin(3A/2) + 2Sin8A / 2Sin11ASin(3A/2) + 2Sin11A

=> 2Sin8A[Sin(3A/2) + 1] / 2Sin11A[Sin(3A/2) + 1]

=> 2Sin8A/2Sin11A

=> Sin8A/Sin11A

= R.H.S

Hence proved.

Answer 2

Step-by-step explanation:

5A+ 2= 7A× 8A= 56A+11A= 67A